package model;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

/**
 * @author 刘浩彬
 * @date 2023/11/12
 */
//通过 BlogDao 来完成针对 blog 表的操作
public class BlogDao {
    // 1. 新增操作（提交博客）
    public void insert(Blog blog){
        Connection connection = null;
        PreparedStatement statement = null;
        try{
            // 1. 先建立连接
            connection = DBUtil.getConnection();
            // 2. 构造 SQL
            String sql = "insert into blog values (null, ?, ?, now(), ?)";
            statement = connection.prepareStatement(sql);
            statement.setString(1, blog.getTitle());
            statement.setString(2, blog.getContent());
            statement.setInt(3, blog.getUserId());
            // 3. 执行 SQL
            statement.executeUpdate();
        }catch (SQLException e){
            throw new RuntimeException();
        }finally {
            DBUtil.close(connection, statement, null);
        }
    }

    // 2. 查询博客列表 （博客列表页）
    // 把数据库里的所有博客都拿到
    public List<Blog> getBlogs(){
        List<Blog> blogList = new ArrayList<Blog>();
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try{
            connection = DBUtil.getConnection();
            String sql = "select * from blog order by postTime desc";
            statement = connection.prepareStatement(sql);
            resultSet = statement.executeQuery();
            while (resultSet.next()){
                Blog blog = new Blog();
                blog.setBlogId(resultSet.getInt("blogId"));
                blog.setTitle(resultSet.getString("title"));
                // blog.setContent(resultSet.getString("content"));
                // 此处读到的是正文是整个文章的内容， 博客列表页，只希望展示出一些摘要
                // 此处需要对 content 做一个简单的截断 substring
                String content = resultSet.getString("content");
                if (content.length() > 100){
                    content = content.substring(0,100) + "...";
                }
                blog.setContent(content);
                blog.setPostTime(resultSet.getTimestamp("postTime"));
                blog.setUserId(resultSet.getInt("userId"));
                blogList.add(blog);
            }
        }catch (SQLException e){
            throw new RuntimeException();
        }finally {
            DBUtil.close(connection, statement,resultSet);
        }
        return blogList;
    }

    // 3. 根据博客 id 查询指定的博客
    public Blog getBlog(int blogId){
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try{
            connection = DBUtil.getConnection();
            String sql = "select * from blog where blogId = ?";
            statement = connection.prepareStatement(sql);
            statement.setInt(1, blogId);
            resultSet = statement.executeQuery();
            // 由于此处是拿着 blogId 进行查询， blogId作为唯一主键，是唯一的
            // 而且查询结果 非 0 即 1， 不需要使用 while 来进行遍历
            if (resultSet.next()){
                Blog blog = new Blog();
                blog.setBlogId(resultSet.getInt("blogId"));
                blog.setTitle(resultSet.getString("title"));
                // 这个方法是期望获取博客详情页面的时候， 调用，不需要进行截断，应该是展示完整的数据内容
                blog.setContent(resultSet.getString("content"));
                blog.setPostTime(resultSet.getTimestamp("postTime"));
                blog.setUserId(resultSet.getInt("userId"));
                return blog;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            DBUtil.close(connection, statement, resultSet);
        }
        return null;
    }

    // 4. 根据博客 id ，删除博客
    public void delete(int blogId){
        Connection connection = null;
        PreparedStatement statement = null;
        try{
            connection = DBUtil.getConnection();
            String sql = "delete from blog where blogId = ?";
            statement = connection.prepareStatement(sql);
            statement.setInt(1, blogId);
            statement.executeUpdate();
        }catch (SQLException throwables){
            throwables.printStackTrace();
        }finally {
            DBUtil.close(connection, statement, null);
        }
    }
}
